The present invention relates to agricultural implements and, in particular, it relates to towable folding wheel rakes useful to form windrows from cut forage.
A primary goal in the harvesting of hay is to dry the hay as soon as possible and remove it from direct exposure to sunlight. The hay must be dried before storage to avoid the problems of mold and spontaneous combustion. Exposing the cut hay to sunlight longer than is required to adequately dry it, however, can result in unacceptable loss of nutritive value of the hay due to deterioration of the protein level.
Typically, hay is harvested into approximately five-foot swaths along the ground, and is exposed to sunlight for the initial stage of the drying process. The swaths of hay are then raked into narrow windrows to remove most of the hay from direct contact with the moist ground. The windrow enhances air circulation within the hay, thereby hastening the drying process.
Many types of wheel rakes have existed for decades. These comprise angled, tined wheels that are propelled across the ground of a field of cut forage. Contact with the ground while traveling across the ground rotates the wheels and thereby rakes the hay in a desired direction. Of particular interest are V-rakes in which at least two banks of rake wheels are deployed in the shape of a V during operation. Generally, V-rakes employ an arm on each side of a frame to support the wheel rakes. Such V-rakes are used to rake forage into a swath or windrow by raking the forage from the outer edges of the implement inward. V-rakes are preferably adjustable so that the width of the windrow produced is variable and the swath raked on each pass is optimal for the circumstances encountered. For optimal operation, it is preferable to be able to independently adjust the angle of the wheel banks, and the width of their separation.
Wheel rakes are subject to repeated structural stresses due to uneven ground and irregular distribution of forage material when propelled through fields of cut hay to form the hay into windrows. The arm assemblies supporting the wheel rakes must have considerable strength in order to bear such stresses successfully. Welded assemblies are thus preferred for their robustness and durability.
Another consideration in wheel rake design is the ability of the rake to compensate for variations in the terrain that it passes over. The raking wheels must have some freedom to move up and down while maintaining a certain amount of downward pressure. This freedom of motion is referred to as flotation and the raking wheel assemblies are said to float to compensate for terrain unevenness. It is preferred that each bank of raking wheels be able to float independently of the other bank and that the raking wheels each have some freedom to float within the bank. Such independent flotation promotes efficient raking, and reduces the risk of operational damage to the equipment. It is further beneficial if the down pressure of the wheel rakes can be adjusted to adapt to varying conditions.
Aside from raking forage efficiently, wheel rakes must be readily transportable from storage to field and between fields. This generally involves passing through fence gates and transportation on public roadways. Since the wheel rake implement is configured to rake a wide swath in use, there must be provided a means to configure the rake more compactly for transport. A wide variety of schemes for accomplishing this have been disclosed in the prior art. Some involve folding the V-rake by raising the wheel supporting arms from a horizontal position used when raking a field to a vertical position for transit. This can be accomplished manually or with powered assist, commonly with hydraulics. Hydraulic folding provides for operator convenience as well as improved safety since the operator need not risk contact with the relatively heavy machinery while it is being folded. V-rakes that fold upward to allow for transport include those disclosed in U.S. Pat. Nos. 4,977,734, and 4,974,407 to Rowe et al., 4,753,063 to Buck, 4,214,428 to Caraway and 4,183,198 to Sligter.
Wheel rake implements must share the public right of way with automotive and pedestrian traffic. Safety concerns dictate that rake arms folded in a vertical position be securely held in their vertical orientation. Accordingly, many folding wheel rake designs include various safety lock devices, such as chains and locking collars to prevent the movement of the rake arms from a vertical position. Safety lock devices can require relatively complex intervention on the part of the operator to engage. Operation and engagement of safety locks should be as simple as possible, to encourage their routine use.
One of the significant costs involved in the production and delivery of hay rakes is that of shipping. Wheel rakes, however, are necessarily bulky in order to accomplish their intended task, and can present extraordinary challenges with regard to shipping. One approach to the challenge of shipping wheel rakes has been to design rakes to be assembled from many small sub-components. Such rakes are shipped disassembled, and can present a quite compact shipping package. This approach, however, creates a rake that is largely bolted together, and more prone to operational damage than a rake that is substantially welded in construction. Additionally, the implement dealer or end user must expend considerable labor to assemble the rake. Welded rakes, on the other hand, offer superior strength and durability but also comprise large individual rake components that do not lend themselves well to compact shipping packages. A V-wheel rake of substantially welded construction, that could be compactly configured for shipping and required minimal assembly upon arrival at its intended location, would provide distinct advantages.
Another factor affecting both the manufacturing and operating cost of hydraulically folded wheel rakes is the number of hydraulic components. Many folding rakes employ multiple hydraulic piston and cylinder assemblies to fold the rake arms. Efforts to reduce costs have lead to the development of linkages that allow a single piston and cylinder assembly to fold both arms. In order to raise the rake arms symmetrically, a variable geometry quadrilateral can be employed. A hydraulic piston and cylinder assembly forms the diagonal of a quadrilateral. When the piston and cylinder assembly is extended, the other diagonal of the quadrilateral is shortened to lift the rake arms. When the piston and cylinder assembly is retracted, the other diagonal is extended to lower the arms. In general, these linkages can be somewhat complex, heavy and often have multiple pivots which require frequent lubrication and tend to wear. U.S. Pat. Nos. 5,313,772 and 5,263,306 to Tonutti, assigned to Tonutti S. P. A., disclose examples of wheel rakes employing a single piston and cylinder assembly in conjunction with a quadrilateral linkage.
A single piston and cylinder assembly could be used to extend between and interconnect the lift arms directly. Particularly if flotation is allowed at the interconnection points, however, a single piston and cylinder raising approach would tend to lift the arms unequally, with one arm being vertical and the other hanging to one side. This creates the appearance, if not necessarily a greater likelihood, that a rake arm may fall while the rake is in transit. It may create anxiety or concern that the rake arms are not entirely raised in the mind of the operator or motorists passing near the rake while it is in transit. It is preferable that rake arms be raised to a symmetrical vertical position.
It would be desirable to produce an economical, towable, folding V-rake, the folding mechanism of which is actuated by a single hydraulic piston and cylinder assembly, which folds the arms to a compact, symmetrical, easily locked, vertical orientation for shipping, transit and storage, without employing a complex linkage. It would be preferable for such a rake to allow for convenient independent adjustment of the angle and width of the raking assemblies and of the down pressure of the raking wheels. The rake would ideally be constructed largely of welded components, to provide a robust wheel rake requiring minimal assembly by the seller or end user.
The present invention in large measure solves the above noted problems, providing a folding rake with an improved folding mechanism. The rake hereof employs a single hydraulic piston and cylinder assembly to fold both arms of a V-rake by a simple, light weight mechanism providing for independent flotation, having relatively few wearing pivot points, and yet still raising the rake arm assemblies to secure vertical positions. Additionally, the V-rake hereof provides for independent adjustment of transport wheel width, rake angle, raking width and wheel down pressure. The towable V-wheel rake of the present invention is uniquely foldable for compact shipping and storage, without the necessity of significant disassembly.
The folding mechanism comprises a single hydraulic piston and cylinder assembly secured at one end to the rake frame or carriage. The hydraulic piston rod engages a tower on a first wheel rake assembly or subframe and rotates the first wheel rake assembly about a pivot point. A linkage assembly includes a bellcrank rotatable about the same first wheel rake assembly pivot point, with the bellcrank linked to a pushrod which is further linked to a second tower on the second wheel rake assembly or subframe. The bellcrank end of the pushrod and the tower end of the pushrod are configured to travel in unequal arcs while the wheel rake assemblies rotate in equal arcs, thereby enabling the arms of the wheel rake assemblies to be raised to a symmetrical vertical transport position, while still providing for flotation of the lift arms, independent of one another, when in the unfolded working position.
When the wheel rake assemblies are in the down, working position for raking, they are supported by adjustable tension compression springs, thus providing for variable down pressure and an independent adjustment of down pressure for each wheel rake assembly.
Each wheel rake assembly further includes a beam carrying a plurality of raking wheels. The beam is pivotably adjustable to vary the angle of the wheel bank carried by the beam relative to the direction of travel of the V-rake. This is accomplished by pivotably fixing one end of a rod to the rake arm and providing a series of connection points spaced upon the beam. The second end of the rod is selectively engageable by any of the connection points.
Additionally, the raking width may be varied independently for each side of the rake. Each rake arm comprises a slider that telescopes in and out relative to a fixed sleeve, and is selectively fixable at a plurality of different positions of width.
The rake frame is carried by ground engaging transport wheels. The wheels are independently adjustable long the width of the frame by clamping them at various locations upon the transverse bar of the wheel rake.